I've added and used some of the OSMF framework to my as3 project in flash builder, every second time i save I get the errors attached in the screenshot, then I can either do a change and save again or clean the project, one of either removes the errors - it is very annoying and time consuming to do so - and suggestions as to how this may be fixed?
From the 1.0 release notes, let us know if this doesn't address your problem:
Using OSMF with the Flex 4.0 SDK
The Flex 4.0 SDK ships with an earlier version of OSMF. If you want to use the Flex 4 SDK with the latest version of OSMF, you need to remove the older version of OSMF. To do so in Flash Builder 4, select File > Properties > Flex Build Path > Library path, select osmf.swc under the Build path libraries, and click the Remove button.